1. Field of the Invention
The present invention relates to a water treatment apparatus, and more particularly, to a water treatment apparatus having a purifying section for purifying water to be treated and a sterilizing section for sterilizing the water that has been treated in the purifying section, and an effective technique for achieving an optimum water quality control using the same apparatus.
2. Description of the Related Art
In a known water treatment apparatus for domestic or industrial wastewater, a water quality detection sensor is used to keep track of the quality of water to be treated. For example, Japanese laid-open patent publication No. 3-52696 discloses a water treatment apparatus of this type. In this apparatus, a DO sensor is provided in an aeration tank disposed upstream of a sterilizing chamber. The DO sensor is employed to keep track of the quality of the aerated water. However, in such a water treatment apparatus in which a water quality detection sensor is disposed in a purification region such as an aeration tank, biomembrane may be deposited on the water quality detection sensor and such biomembrane inhibits accurate water quality detection.